Development of a Headspace-Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS) Method for the Determination of Benzene in Soft Drinks

A method based on headspace-solid phase microextraction and gas chromatography with mass spectrometry has been developed and validated for the determination of benzene in soft drinks. The extraction step was optimized using a rotatable central composite design including the following experimental variables: extraction temperature, extraction time, sample weight, and salt concentration. The optimized procedure, which was carried out at 30 A degrees C during 30 min by using a 75 mu m carboxen-polydimethylsiloxane fiber, showed good linearity within the concentration range 0-25 mu g kg(-1) (r (2) > 0.999), mean recoveries from 97.5 to 103.1 %, and coefficients of variation from 1.5 to 13.4 % for repeatability and from 1.5 to 15.7 % for within-laboratory reproducibility. Limits of detection and quantification were calculated at 0.02 and 0.08 mu g kg(-1), respectively. The method was applied to determine the concentrations of benzene in 77 samples of beverages from the Brazilian market. Levels from < 0.08 to 10.84 mu g kg(-1) were obtained, which are comparable to those verified in other countries. Most of the samples (72.2 %) contained benzene up to 1 mu g kg(-1).